'In 1935, Marcel Duchamp published Rotoreliefs, a set of 6 double sided discs meant to be spun on a turntable at 40–60 rpm. Duchamp and Man Ray filmed early versions of the spinning discs for the short film Anémic Cinéma. A manifestation of Duchamp’s interest in optical illusions and mechanical art, the two-dimensional rotoreliefs create an illusion of depth when spun at the correct speed. These rotoreliefs were produced in an edition of 500, and were initially displayed and offered for sale at the Concours Lépine inventor’s fair.'
http://thebluelantern.blogspot.co.uk/2012/08/the-marvelous-rotoreliefs-of-marcel_25.html